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Jan. 21, 1947. F, MlLLER 2,414,656

SOUND PRODUCING INSTRUMENT Filed Sept. 27, 1943 HTTOIQNEX Patented Jan. 21,1947

UNITED STATES PATENT OFFICE SOUND PRODUCING Milo F. Miller, Kansas .Gity, Mn.

Application September 27, I943,#S.erla lo.-503;9.63

7 Claims. 1 This invention relates to sound producing instruments of the percussion type and has for a primary object the provision of .means for developing an over-tone audible to a human car which has become deficient in detecting tones of different frequencies.

One of the important aims of the present invention is to provide a sound producing instrument having at least two vibrating elements,-each capable of emitting tones of different frequencies, which tones are so related as to develop a pulsating or an undulating over-tone audible to certain persons who .have =lost the property of detecting and hearing tones having the frequencies of the sounds emitted by the two respective elements.

.A still further aim of the instant invention is to provide a unitary instrument having as a component part thereof, at least two sounding bars associated with resonating chambers, said bars andchambers being relatively adjustable for the purpose of developing individual sound waves of such frequency as to-create an over-tone audible to the operator.

Other objects of the invention will appear during the course of the following specification, referring to the accompanying drawing wherein:

Fig. 1 is a bottom view of a sound producing instrument made in accordance with the present invention illustrating one unit of the resonating tube assembly.

Fig. 2 is a longitudinal sectional view thereof taken on line .IIII of Fig. 1.

Fig. 3 is a cross sectional view taken on line III-III of Fig. 2 and looking in the direction of the arrow.

Fig. 4 is a bottom view of the sound producing instrument, completely assembled and showing a pair of tone elements.

Fig. 5 is a diagrammatical view illustrating the sound wave from a pair of sound producing instruments and showing in a schematical fashion, the undulating overtone waves; and

Fig. 6 is a wiring diagram illustrating the man nor of arranging the striking means of the instrument whereby the sounding bars are successively struck at intervals.

It has been found that persons unable to detect tones of conventional frequencies may be made to hear sounds of several lengths produced by combining two frequencies to establish an over-tone. It has further been discovered that the component sounds must be altered with respect to frequencies, pitch and timbre in order to establish the over-tone audible to those hard til r .2 hi hearing. Accordingly, sound producing instruments heretofore available, have not been satisfactory to meet the problem of providing deviations audible to those so afflicted. The instrument illustrated permits all of the necessary adjustments to produce the basic sound waves from which emanate the over-tone or undulating reverberation "of the two originaltrains of waves. The instrument capable of obtaining sounds audible to those afflicted with various stages of deafness comprises at least two resonating tubes ill and associated vsoundingybars l2. Said resonating tubes in and. sounding bars l2 are suitably supported by a base IA in the nature of a housing wherein is carried a solenoid 16 for each bar 12. The striking member -18 is operated when sole- .noid iBLis energized. A plate I5 joins base membars 14 as shown in .Fig. 4.

Resonating tubes 1-0 are alike in length and diameter, the-chamber 2-0 therein may be varied as to length through the medium of a pair of pistons 222 slidably disposed near the ends of tubes 10 and manuallymanipulable through axial rods .24.

A scale 26 carried by base I4 cooperates with pointer 28in indicating to the operator the rela- .tive positions of pistons '22. This is particularly important since it is desired that pistons 22 be the same distance from opening 39 formed through the side of eachtube [0.

Circular :opening .36 is on a transverse medial line LQf each tube :10 and the size thereof is selectively varied :by .a :series of shutters 32 all slidably mounted within the respective tubes It for movement to and from a desired position. Thus, not only can the chambers 20 of the tubes Ill be altered as to cubicle capacity, but the size of openings 30 may be varied to suit conditions and present a tone quality which cooperates with frequency to establish a sound wave, characterized by having a quality capable of combining with the sound waves produced by the companion tube In in creating the overtone audible to those hard of hearing.

Sounding bars 12 are of different widths and lengths to produce different tones. The quality of said tones and the manner of resonating the same are not only alterable by adjustment of the parts associated with tubes l0, but may be altered by moving bars l2 toward and from opening 30 in resonating tubes l0 through the medium of supporting nuts 34 which carry bushings 36 of non-metallic material.

It is desirable to strike one of bars l2 after the other has been struck, and within the period of time of vibration of the first struck ban-thus, two distinct sound waves of different wave lengths or frequencies are created to combine as shown diagrammatically in Fig. 5, wherein line,

38 represents one frequency, line 40 the second tone frequency, and the dotted line 42 illustrates the over-tone which is of the desirable wave length.

A single operation will cause both bars to sound in the proper-sequence and at the proper time when an electrical circuit such as shown in Fig. 6 is employed.

Solenoids l6 are associated with bars I2 as above set forth, and the striking elements l8 are movable when their respective coils are energized. A source of electrical current 44 in the form of a battery or the like, is connected to solenoid l6 by appropriate conductors having a switch 46 therein to open and close the circuit.

Contact points 48 are successively struck by arm 50 as it is moved through its path of travel about pivotal point 52 by solenoid 54. Thus, when switch 46 is closed,solenoid 54 will be energized and arm 50 will be drawn across point 48, one after the other. The two bars I2 will be successively struck and the second will be vibrated by its respective element l8 before the vibration period of the first to be struck is closed.

The sound waves produced as shown diagrammatically in full lines in Fig, 5, will periodically come together to produce an over-tone.

From the foregoing it will be apparent that instruments constructed as set forth, are capable of adjustment and tuning to establish a tone particularly peculiar to one hard of hearing, and that the adjustment of the two basic tones to produce the third over-tone audible to the person hard of hearing, may take place by employing the instrument described and shown. Such variations as may be required in the structure to vary the size of the chamber of the resonating tubes Ill and the size and relativeposition of bars l2, may be made without departing from the spirit of the invention or scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A sound producing instrument of the character described, comprising at least two perforated, closed end resonating tubes; a sounding bar adjacent to each tube and opposite the perforations thereof; and manually manipulable structure mounted on each tube for moving the ends of the tube for varying the size of the chamber thereof.

2. A sound producing instrument of the character described comprising at least two centrally perforated, closed end resonating tubes; a sounding bar opposite the perforation in each tube respectively; means for mounting the sounding bars for movement toward and from the resonating tubes; and. manually manipulable structure for moving the ends of the tubes for varying the size of the chamber of the tubes.

3. A sound producing instrument of the character described comprising at least two resonating tubes; a sounding bar adjacent to each tube; and structure mounted on each tube for varying the size of the chamber thereof, said tubes each having an opening opposing the sounding bar, the tubes each having means thereon for varying the size of the said opening therein.

4. A sound producing instrument of the character described comprising a pair of resonating tubes of like size; a sounding bar adjacent to each tube; means for varying the size of the chamber of each resonating tube respectively; mounting structure for the sounding bars having means for holding the bars predetermined distances from their respective tubes; striking means for each bar respectively, and common means for actuating said striking means at different times, said common means having parts for establishing a period between the times of striking of the bars that is shorter than the duration of vibration of the first to be struck of said sounding bars.

5. A sound producing instrument as set forth in claim 4, wherein the sounding bars are of different width and length.

6. A sound producing instrument as set forth in claim 4, wherein the sounding bars are formed to vibrate at relatively different frequencies.

7. A sound producing instrument of the character described, comprising a pair of resonating tubes; a sounding bar adjacent to each tube; and means for striking the bars at different times, said means having parts for establishing a period between the times of striking being shorter than the duration of vibration of the first to be struck, said tubes and the bars being relatively tuned to produce a third over-tone of deeper timbre and lower frequency than those produced by the sound emitted from the two tubes and their bars.

MILO F. MILLER. 

